Bug 960465 patch 2 - Add method to return a modified version of a style context, with all or part of the animation data removed. r=birtles

This is used in patch 3.

layout/base/RestyleManager.h

@@ -114,6 +114,10 @@ public:
     return mSkipAnimationRules;
   }
 
+  void SetSkipAnimationRules(bool aSkipAnimationRules) {
+    mSkipAnimationRules = aSkipAnimationRules;
+  }
+
   // Whether rule matching should post animation restyles when it skips
   // styles associated with animation.  Only true when
   // SkipAnimationRules() is also true.
@@ -123,6 +127,10 @@ public:
     return mPostAnimationRestyles;
   }
 
+  void SetPostAnimationRestyles(bool aPostAnimationRestyles) {
+    mPostAnimationRestyles = aPostAnimationRestyles;
+  }
+
   // Whether we're currently in the animation phase of restyle
   // processing (to be eliminated in bug 960465)
   bool IsProcessingAnimationStyleChange() const {

layout/style/nsStyleSet.cpp

@@ -1649,6 +1649,28 @@ nsStyleSet::ResolveStyleWithReplacement(Element* aElement,
                     elementForAnimation, flags);
 }
 
+already_AddRefed<nsStyleContext>
+nsStyleSet::ResolveStyleWithoutAnimation(dom::Element* aTarget,
+                                         nsStyleContext* aStyleContext,
+                                         nsRestyleHint aWhichToRemove)
+{
+  RestyleManager* restyleManager = PresContext()->RestyleManager();
+
+  bool oldSkipAnimationRules = restyleManager->SkipAnimationRules();
+  restyleManager->SetSkipAnimationRules(true);
+  bool oldPostAnimationRestyles = restyleManager->PostAnimationRestyles();
+  restyleManager->SetPostAnimationRestyles(false);
+
+  nsRefPtr<nsStyleContext> result =
+    ResolveStyleWithReplacement(aTarget, aStyleContext->GetParent(),
+                                aStyleContext, aWhichToRemove,
+                                eSkipStartingAnimations);
+
+  restyleManager->SetPostAnimationRestyles(oldPostAnimationRestyles);
+  restyleManager->SetSkipAnimationRules(oldSkipAnimationRules);
+
+  return result.forget();
+}
 
 already_AddRefed<nsStyleContext>
 nsStyleSet::ResolveStyleForNonElement(nsStyleContext* aParentContext)

layout/style/nsStyleSet.h

@@ -144,6 +144,15 @@ class nsStyleSet
                               nsRestyleHint aReplacements,
                               uint32_t aFlags = 0);
 
+  // Resolve style by returning a style context with the specified
+  // animation data removed.  It is allowable to remove all animation
+  // data with eRestyle_ChangeAnimationPhase, or by using any other
+  // hints that are allowed by ResolveStyleWithReplacement.
+  already_AddRefed<nsStyleContext>
+    ResolveStyleWithoutAnimation(mozilla::dom::Element* aElement,
+                                 nsStyleContext* aStyleContext,
+                                 nsRestyleHint aWhichToRemove);
+
   // Get a style context for a non-element (which no rules will match),
   // such as text nodes, placeholder frames, and the nsFirstLetterFrame
   // for everything after the first letter.